1. Field of the Invention
This invention concerns novel, plied yarns containing alternating S and Z regions of false-twist and a novel method for the manufacture of such yarns. More particularly, the plied yarns of this invention contain, for the purpose of introducing a special effect, one ply having a distinctively different property from at least two other plies.
2. Description of the Prior Art
In textile yarns, it is common practice to employ one or more plies of an "effect" yarn to modify the properties of the resulting plied yarn. The results of the modification depend upon the particular manner in which the yarns are combined with one another. For example, a low denier, antistatic yarn when ply-twisted with a heavy denier, multifilament, bulked, carpet yarn is known in the art to provide better antistatic protection in the plied yarn when ply-twisted under conditions result in the antistatic yarn being located more frequently at or near the surface of the plied yarn.
Plied, twist-stable, yarn structures comprising a plurality of strands which are plied about one another by alternating S and Z regions of twist and the preparation of such structures are described in U.S. Pat. No. 3,225,533 and in British Pat. Spec. No. 1,047,503. U.S. Pat. No. 3,468,120 describes a method for the preparation of such yarns having improved quality; however, when a modifying yarn such as an antistatic yarn is employed as one of the strands in this method, the most desirable results are not necessarily obtained. Such factors as the manner in which the different strands ply with one another and the sensitivity of the desired modification to the final, plied yarn configuration affect the results.